Renealmia longicarpa Dhetchuvi & Eb.Fisch., 2024

Fischer, Eberhard & Dhetchuvi, Jean-Baptiste M. M., 2024, A revision of the genus Renealmia (Zingiberaceae) in Tropical Africa. I. New species from Central Africa (Cameroon, Rio Muni, Gabon, Democratic Republic of the Congo), and notes on the identity of Renealmia africana, R. congolana, and R. dewevrei, Phytotaxa 674 (1), pp. 55-96 : 64

Renealmia longicarpa Dhetchuvi & Eb.Fisch. , sp. nov. ( Figs 7–9 , 29).

Type: — GABON. Estuaire, Monts de Cristal, route de Kinguélé, 19 January 1968, N. Hallé & J.F. Villiers 4587 (holotype P MNHN-P- P 00072213!).

Diagnosis: —The new species differs from all African species in the elongate trigonous fruits (30 × 5–8 mm) on lax cincinni with 1–3 flowers that are recurved downwards and the caducous bracts and bracteoles.

Description: —Perennial herb forming dense clump. Leafy shoots c. 100 cm tall, covered at base with one leafless sheath. Leaves with sheaths with reticulately anastomosing venation and numerous simple and branched glands between reticulations. Petiole reticulate, 3.0– 3.5 cm long, with simple glands between reticulations. Ligule obtuse, up to 2 mm long, with 2 short lobes and branched glands on external surface. Lamina oblanceolate, papyraceous, attenuate at base and decurrent on apex of petiole, short-acuminate at apex, about 20–27 cm long and 6.5–7.0 cm wide, glabrous, median vein reticulate and glabrous, lateral veins anastomosing, greyish-green at lower surface, lateral veins prominent and well visible on lower surface. Inflorescence thyrsic, arising at base of leafy shoots, up to 52 cm long, entirely covered with simple and branched hairs; peduncle about 37 cm long, green, with elongate articulation, median up to 10 cm long, pubescent, with minute branched hairs, with sheaths up to 6 cm long, pubescent, with long ciliate hairs at margin and apex and short hairs in middle part, rachis about 15 cm long, with branched hairs. Bracts caducous, membranaceous, about 1 cm long; bracteoles caducous, membranaceous, about 5 mm long; partial inflorescences (cincinni) subsessile, with 1 to 3 flowers; pedicels green, sparsely pubescent, with minute hairs, about 13 mm long, regularly enlarged at apex. Calyx green, corolla and stamen not known. Fruits trigonous, elongated, recurved downwards, with 3 longitudinal crests, surface irregular, c. 30 mm long and 5–8 mm in diameter, glabrous, red-orange, dehiscence from the base. Seeds globose to irregular, grey, 3 mm in diameter, 8–9 per locule, aril transparent-yellow.

Distribution: —Only known from the Crystal Mountains, Gabon.

Habitat: —Submontane dense rainforest, 730 m.

Etymology: —The specific epithet refers to the long fruits.

Preliminary IUCN conservation assessment: —With only one site where Renealmia longicarpa has been observed, it is not possible to calculate the extent of occurrence (EOO). The area of occupancy (AOO) with 9 km ² meets the criteria of the Critically Endangered category (CR) under sub-criterion B2. One major threat is deforestation, but the only known location lies inside a protected area (Parc National des Monts Crystal). There are two herbarium sheets collected in 1968 and 2019, which indicate that it is rare. The species is thus assessed here as Least Concern (LC), Conservation dependent (CD).

Additional specimens seen (Paratypes): — GABON. Estuaire, Monts de Cristal, vers le secteur Mont Séni, Concession BSG, entre Kougouleu et Médouneu, 730 m, 8 March 2019, P. Barberá, E. Bidault, E. Akouangou, J.D. Kaparidi & D. Ngeba-Ikapi 2529 (BRLU!, LBV, MO).

Figures

FIGURE 7. Renealmia longicarpa. Holotype, P. Reproduced with permission from P.

FIGURE 8. Renealmia longicarpa. A, C. Detail of infructescence. B. Leafy shoot. D. Rhizome. Photographs: P. Barberá. A–D from Barberá, Bidault, Akouangou, Kaparidi & Ngueba Ikapi 2529. Reproduced with permission.

FIGURE 9. Renealmia longicarpa. A. Leaf. B. Infructescence. C. Detail of infructescence. A–C from Hallé & Villiers 4587. Illustration by E. Fischer. Scale bars:A–C. 1 cm.